U.S. Pat. No. 4,954,009 of Kellison shows concrete barriers anchored to a road surface by bolts extending through holes in the barriers.
U.S. Pat. No. 4,605,336 of Slaw provides a precast concrete parapet that has reinforcing bars which run outside of the precast shape in order to pass around a locking bar for anchoring the parapet in place.
U.S. Pat. No. 5,131,786 of House et al. also has reinforcing rods extending outside of a precast concrete barrier for anchoring purposes. Otherwise, the precast concrete of House et al. is reinforced by welded wire fabric.